From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45370) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zk7w4-0004LK-20 for qemu-devel@nongnu.org; Thu, 08 Oct 2015 05:56:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zk7vM-0004EH-Sw for qemu-devel@nongnu.org; Thu, 08 Oct 2015 05:56:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36311) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zk7vL-0004Cr-Hy for qemu-devel@nongnu.org; Thu, 08 Oct 2015 05:55:44 -0400 Date: Thu, 8 Oct 2015 11:55:37 +0200 From: Marc =?UTF-8?B?TWFyw60=?= Message-ID: <20151008115537.1b2a6a58@markmb_rh> In-Reply-To: <20151006142925.GB6361@morn.lan> References: <1444089115-28710-1-git-send-email-kevin@koconnor.net> <5613788A.1070409@redhat.com> <20151006142925.GB6361@morn.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCHv2] fw_cfg: Define a static signature to be returned on DMA port reads List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin O'Connor Cc: Stefan Hajnoczi , Laszlo Ersek , qemu-devel@nongnu.org On Tue, 6 Oct 2015 10:29:25 -0400 "Kevin O'Connor" wrote: > On Tue, Oct 06, 2015 at 09:30:18AM +0200, Laszlo Ersek wrote: > > On 10/06/15 01:51, Kevin O'Connor wrote: > > > Return a static signature ("QEMU CFG") if the guest does a read > > > to the DMA address io register. > > > > > > Signed-off-by: Kevin O'Connor > > > --- > > > > > > Marc, if you decide to respin your fw_cfg series, I've updated > > > the dma signature patch. This addresses the comments from > > > Stefan, and I hope it addresses the comments from Laszlo. > > > > Thank you -- I didn't know about extract64(). > > > > The patch looks good to me, but I think the QEMU coding style > > requries /* ... */ comments, and forbids //. > > I always forget about that one. Marc, if you do respin the series I > updated the patch below. > This patch doesn't apply without the series. I'll add it to the series and send it as soon as posible. Thanks Marc > > > commit 02a449ece95da00fa64a9c704555c6afa8e03579 > Author: Kevin O'Connor > Date: Thu Oct 1 14:16:59 2015 +0200 > > fw_cfg: Define a static signature to be returned on DMA port reads > > Return a static signature ("QEMU CFG") if the guest does a read > to the DMA address io register. > > Reviewed-by: Stefan Hajnoczi > Signed-off-by: Kevin O'Connor > > diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt > index 2d6b2da..cbdce7d 100644 > --- a/docs/specs/fw_cfg.txt > +++ b/docs/specs/fw_cfg.txt > @@ -93,6 +93,9 @@ by selecting the "signature" item using key 0x0000 > (FW_CFG_SIGNATURE), and reading four bytes from the data register. If > the fw_cfg device is present, the four bytes read will contain the > characters "QEMU". > +If the DMA interface is available, then reading the DMA Address > +Register returns 0x51454d5520434647 ("QEMU CFG" in big-endian > format). + > === Revision / feature bitmap (Key 0x0001, FW_CFG_ID) === > > A 32-bit little-endian unsigned int, this item is used to check for > enabled diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c > index 59933b3..5098bfc 100644 > --- a/hw/nvram/fw_cfg.c > +++ b/hw/nvram/fw_cfg.c > @@ -53,6 +53,8 @@ > #define FW_CFG_DMA_CTL_SKIP 0x04 > #define FW_CFG_DMA_CTL_SELECT 0x08 > > +#define FW_CFG_DMA_SIGNATURE 0x51454d5520434647 /* "QEMU CFG" */ > + > typedef struct FWCfgEntry { > uint32_t len; > uint8_t *data; > @@ -393,6 +395,13 @@ static void fw_cfg_dma_transfer(FWCfgState *s) > trace_fw_cfg_read(s, 0); > } > > +static uint64_t fw_cfg_dma_mem_read(void *opaque, hwaddr addr, > + unsigned size) > +{ > + /* Return a signature value (and handle various read sizes) */ > + return extract64(FW_CFG_DMA_SIGNATURE, (8 - addr - size) * 8, > size * 8); +} > + > static void fw_cfg_dma_mem_write(void *opaque, hwaddr addr, > uint64_t value, unsigned size) > { > @@ -416,8 +425,8 @@ static void fw_cfg_dma_mem_write(void *opaque, > hwaddr addr, static bool fw_cfg_dma_mem_valid(void *opaque, hwaddr > addr, unsigned size, bool is_write) > { > - return is_write && ((size == 4 && (addr == 0 || addr == 4)) || > - (size == 8 && addr == 0)); > + return !is_write || ((size == 4 && (addr == 0 || addr == 4)) || > + (size == 8 && addr == 0)); > } > > static bool fw_cfg_data_mem_valid(void *opaque, hwaddr addr, > @@ -488,6 +497,7 @@ static const MemoryRegionOps fw_cfg_comb_mem_ops > = { }; > > static const MemoryRegionOps fw_cfg_dma_mem_ops = { > + .read = fw_cfg_dma_mem_read, > .write = fw_cfg_dma_mem_write, > .endianness = DEVICE_BIG_ENDIAN, > .valid.accepts = fw_cfg_dma_mem_valid, >